LONG-TERM MONITORING OF THE LEES FERRY FISHERY: UPDATE

AMWG – January 27, 2016

Lisa Winters, Bill Stewart, Dave Rogowski, Robin Osterhoudt, Pilar Wolters, Kristy Manuell

Goal • To maintain a quality rainbow trout fishery in Glen Canyon

Photo: George Andrejko

NPS Comprehensive Fisheries Management Plan

• Relative Abundance rainbow trout CPUE > 1 fish/minute (fall e-fishing)

• Recruitment rainbow trout < 152 mm TL make up greater than 20% of catch (fall e-fishing)

• Angler Catch catch rates ≥ 0.5 fish/ hour, with average size > 14”

Angler Recommendations • Size structure indicative of a stable

rainbow trout population (YOY 20-50%)

• Angler catch rates >1 fish/hour for rainbows ≥14”

• Angler catch rates >0.1 fish/hour for rainbows ≥20”

• Robust trout body condition (Kn ≥1.0 in summer)

• A diverse aquatic food base with 10% abundance of EPT species

AGFD Fisheries Management Plan

Fisheries Management Plan –Colorado River Lees Ferry

Parameters Objective Guideline Strategies if Objectives are not met

OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to support recreational fishing.

Recruitment

Abundance

Rainbow trout ≤ 6 inches compose 20% - Stocking 50% of the population (determined by fall Trout management flows electrofishing) HFEs Rainbow trout electrofishing CPUE exceeds Stocking 1 fish/minute (all sizes of trout) HFEs

Change in regulations

Fisheries Management Plan –Colorado River Lees Ferry

Parameters Objective Guideline Strategies if Objectives are not met OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to support recreational

fishing. Recruitment Rainbow trout ≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing)

Stocking Trout management flows HFEs

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout)

Stocking HFEs Change in regulations

Abundance

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate

Angler catch rate ≥ 1 rainbow trout/hour Stocking HFEs Change in regulations

Fisheries Management Plan –Colorado River Lees Ferry

Parameters Objective Guideline Strategies if Objectives are not met OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to support recreational

fishing. Recruitment Rainbow trout ≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing)

Stocking Trout management flows HFEs

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout)

Stocking HFEs Change in regulations

Abundance

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate

Angler catch rate ≥ 1 rainbow trout/hour Stocking HFEs Change in regulations

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Angler Catch Quality

10 rainbow trout ≥ 14 inches caught by the angler in a 10-hour day; one ≥ 20 inches caught by angler in 10 hour day

Maintain trout condition factor ≥ 1 during the summer months

Food base enhancement Trout management flows Change in regulations

Fisheries Management Plan –Colorado River Lees Ferry

Parameters Objective Guideline Strategies if Objectives are not met OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to support recreational

fishing. Recruitment Rainbow trout ≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing)

Stocking Trout management flows HFEs

Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout)

Stocking HFEs Change in regulations

Abundance

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate

Angler catch rate ≥ 1 rainbow trout/hour Stocking HFEs Change in regulations

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Angler Catch Quality

10 rainbow trout ≥ 14 inches caught by the angler in a 10-hour day; one ≥ 20 inches caught by angler in 10 hour day

Maintain trout condition factor ≥ 1 during the summer months

Food base enhancement Trout management flows Change in regulations

OBJECTIVE 4 – Avoid catastrophic failure of the trout population, and establish protocols for emergency recovery from population loss.

Water Quality Dissolved oxygen ≥ 5 mg/l as measured at outflow from GCD.

Flow manipulation Temperature control device Use of river outlet tubes

If failure of multiple age classes is documented by electrofishing and <0.25 trout/hour documented in creel surveys, mitigation will be necessary.

Stocking Translocation of fish

Catastrophic Failure of Population

Objective 1 – Maintain a healthy population of rainbow trout at Lees Ferry to support recreational fishing

Young of the Year (fall only) 1.00

0.80

0.60 65%

0.40

0.20

0.00 1990 1995 2000 2005 2010 2015

Year

Frac

tion

of y

oung

of t

he y

ear r

ainb

ow tr

out

capt

ured

in th

e fa

ll

Young of the Year (fall only)

1.4 YOY/min

Rainbow Trout CPUE (boat) R

ainb

ow tr

out C

PUE

(fis

h/m

in)

0

2

4

6

8

10

2.2 fish/min

1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Year

Objective 2– provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Objective 3– grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Creel • 1,989 anglers interviewed

• 1,557 upriver • 432 walk-in

• 12,658 rainbow trout caught

Angler

Boaters

Walk-in

CPUE (fish/hr)

1.06

0.25

Angler Catch Rates

Angler Catch Rates

• No accurate representation of size of fish anglers catch

• Change creel question to “how many fish over 14 inches, howmany of those were over 20 inches?”

Total length (mm)

Freq

uenc

y

Angler Catch Rates 150

100

50 100 150 200 250 300 350 400

Total Length (mm)

spring

summer

fall

0

50

0

50

100

150

0

50

100

150

Num

ber o

f Fis

h

• No accurate representation of size of fish anglers catch

• Change creel question to “how many fish over 14 inches, howmany of those were over 20 inches?”

450

Condition 0.99

1.00

1.08

Objective 4– avoid catastrophic failure of the trout population, and establish protocols for recovery from population loss

Dissolved Oxygen

Year Classes

150

100

50

0

150

Freq

uenc

y

100

50

0

150

100

50

0

spring

summer

fall

50 100 150 200 250 300 350 400 450 Total length (mm)

Angler Catch Rates

Fisheries Management Plan –Colorado River Lees Ferry

Parameters Objective Guideline 2015 Status OBJECTIVE 1 - Maintain a healthy population of rainbow trout at Lees Ferry to support recreational

fishing. Recruitment Rainbow trout ≤ 6 inches compose 20% -

50% of the population (determined by fall electrofishing)

64% Rainbow trout electrofishing CPUE exceeds 1 fish/minute (all sizes of trout) 2.22 fish/min

Abundance

OBJECTIVE 2 – Provide a quality trout fishing experience with catch frequency commensurate with the Blue Ribbon status of the fishery.

Angler Catch Rate

Angler catch rate ≥ 1 rainbow trout/hour Boat = 1.06 fish/hr Walk-in = 0.25 fish/hr

OBJECTIVE 3 – Grow quality sized trout that are available to the angler, consistent with the Blue Ribbon status of the fishery.

Angler Catch Quality

10 rainbow trout ≥ 14 inches caught by the angler in a 10-hour day; one ≥ 20 inches caught by angler in 10 hour day

Maintain trout condition factor ≥ 1 during the summer months

0.01 fish/hr (>18”)

Kn = 0.99 - 1.08 OBJECTIVE 4 – Avoid catastrophic failure of the trout population, and establish protocols for emergency

recovery from population loss. Water Quality Dissolved oxygen ≥ 5 mg/l as measured at

outflow from GCD. 5.06 - 10.22 at Ferry If failure of multiple age classes is documented by electrofishing and <0.25 trout/hour documented in creel surveys, mitigation will be necessary.

See above; multiple age classes exist

Catastrophic Failure of Population

Species Composition

Species Spring March

Summer July

Fall October Total Percent of

Catch

Rainbow Trout 587 895 1018 2500 97.1%

Brown Trout 8 18 27 53 2.1%

Common Carp 1 1 0 2 0.1%

Flannelmouth Sucker 1 0 17 18 0.7%

Walleye 0 3 0 3 0.1%

53

Species Composition

Species Spring March

Summer July

Fall October Total Percent of

Catch

Rainbow Trout 587 895 1018 97.1%

Brown Trout 8 18 27 2.1%

Common Carp 1 1 0 0.1%

Flannelmouth Sucker 1 0 17 18 0.7%

Walleye 0 3 0 3 0.1%

2500

2

Nonnative Sampling • One night in during July monitoring • Carp at -12 mile slough

• Depletion sampling • 110, 48, 50 by pass • 54% recaptures • Estimated 290 [244,393] carp total in slough

• 8 walleye, 3 flannelmouth and 43 green sunfish caught

     

   

                                          

Nonnative Sampling • Typical July Nonnative monitoring sites:

Night 1: Nonnative Sampling

RM Side Comments RM Side Comments ‐15.78 R R Below Spillway ‐12.05_L L Slough

‐15.78 L L Below Spillway ‐12.19_L L Slough

‐14.3 L L 14 mile Spring ‐12.35_L L Slough

‐14.0 L L Rocky Shoreline Habitat ‐12.15_LS L Slough

‐13.7 R R Spring Inflow

‐13.5 L L Spring Inflow

‐11.0 R R Below Ferry Swale Bar ‐10.9 L L Rocky Shoreline Habitat ‐6.9 L L Backwater Feature

‐3.3 L L Warm Spring Inflow

‐1.5 L L Backwater Feature

• Other spots we are missing? • Timing of surveys? • As conditions may become better for nonnative invasions..

Camera Creel • Better idea of the usage of the fishery • June 2015 – June 2016 • Picture every 30 seconds during daylight hours • Correspond with our 6 days per month of in person creel • Novel technique

Camera Creel • ImageJ software

• Timelapse Program • Mark boats when they launch

on the river and travel upstream, mark when return

• Not counting downstream rafts, not counting CRD rafts

• Creel is only 6 days permonth from 12-6pm • This counts those we miss • This counts non-anglers

• Initial results show we account for 30% more anglers in the camera creel

Summary • AGFD has a Fisheries Management Plan – Colorado

River Lees Ferry • Electrofishing CPUE of rainbow trout is not as bad as we thought it

would be after the “crash” • Angler CPUE okay…

• More brown trout than normal • Green sunfish - Is our nonnative sampling good enough?

• Use of camera creel to better inform angler usage

Acknowledgments • USGS – Grand Canyon Monitoring and Research Center • Fantastic volunteers • St. Jude’s Enterprises, LLC. Boatmen • Creel guru, Steve Harding